/* $FreeBSD: releng/11.2/sys/dev/usb/usb_transfer.c 331722 2018-03-29 02:50:57Z eadler $ */
/*-
 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifdef USB_GLOBAL_INCLUDE_FILE
#include USB_GLOBAL_INCLUDE_FILE
#endif

#undef USB_DEBUG_VAR
#define USB_DEBUG_VAR usb_debug

struct usb_std_packet_size {
    struct {
        uint16_t min;        /* inclusive */
        uint16_t max;        /* inclusive */
    }    range;

    uint16_t fixed[4];
};

static usb_callback_t usb_request_callback;

static const struct usb_config usb_control_ep_cfg[USB_CTRL_XFER_MAX] = { /*lint -e26*/

    /* This transfer is used for generic control endpoint transfers */

    [0] = {
        .type = UE_CONTROL,
        .endpoint = 0x00,    /* Control endpoint */
        .direction = UE_DIR_ANY,
        .bufsize = USB_EP0_BUFSIZE,    /* bytes */
        .flags = {.proxy_buffer = 1,},
        .callback = &usb_request_callback, /*lint !e546*/
        .usb_mode = USB_MODE_DUAL,    /* both modes */
    },

    /* This transfer is used for generic clear stall only */

    [1] = {
        .type = UE_CONTROL,
        .endpoint = 0x00,    /* Control pipe */
        .direction = UE_DIR_ANY,
        .bufsize = sizeof(struct usb_device_request),
        .callback = &usb_do_clear_stall_callback, /*lint !e546*/
        .timeout = 1000,    /* 1 second */
        .interval = 50,    /* 50ms */
        .usb_mode = USB_MODE_HOST,
    },
}; /*lint +e26*/

/* function prototypes */

static void    usbd_update_max_frame_size(struct usb_xfer *);
static void    usbd_transfer_unsetup_sub(struct usb_xfer_root *, uint8_t);
static void    usbd_control_transfer_init(struct usb_xfer *);
static int    usbd_setup_ctrl_transfer(struct usb_xfer *);
static void    usb_callback_proc(struct usb_proc_msg *);
static void    usbd_callback_ss_done_defer(struct usb_xfer *);
static void    usbd_callback_wrapper(struct usb_xfer_queue *);
static void    usbd_transfer_start_cb(void *);
static uint8_t    usbd_callback_wrapper_sub(struct usb_xfer *);
static void    usbd_get_std_packet_size(struct usb_std_packet_size *ptr,
            uint8_t type, enum usb_dev_speed speed);

/*------------------------------------------------------------------------*
 *    usb_request_callback
 *------------------------------------------------------------------------*/
static void
usb_request_callback(struct usb_xfer *xfer, usb_error_t error)
{
    if (xfer->flags_int.usb_mode == USB_MODE_DEVICE)
        usb_handle_request_callback(xfer, error);
    else
        usbd_do_request_callback(xfer, error);
}

/*------------------------------------------------------------------------*
 *    usbd_update_max_frame_size
 *
 * This function updates the maximum frame size, hence high speed USB
 * can transfer multiple consecutive packets.
 *------------------------------------------------------------------------*/
static void
usbd_update_max_frame_size(struct usb_xfer *xfer)
{
    /* compute maximum frame size */
    /* this computation should not overflow 16-bit */
    /* max = 15 * 1024 */

    xfer->max_frame_size = xfer->max_packet_size * xfer->max_packet_count;
}

/*------------------------------------------------------------------------*
 *    usbd_get_dma_delay
 *
 * The following function is called when we need to
 * synchronize with DMA hardware.
 *
 * Returns:
 *    0: no DMA delay required
 * Else: milliseconds of DMA delay
 *------------------------------------------------------------------------*/
usb_timeout_t
usbd_get_dma_delay(struct usb_device *udev)
{
    const struct usb_bus_methods *mtod;
    uint32_t temp;

    mtod = udev->bus->methods;
    temp = 0;

    if (mtod->get_dma_delay) {
        (mtod->get_dma_delay) (udev, &temp);
        /*
         * Round up and convert to milliseconds. Note that we use
         * 1024 milliseconds per second. to save a division.
         */
        temp += 0x3FF;
        temp /= 0x400;
    }
    return (temp);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_setup_sub_malloc
 *
 * This function will allocate one or more DMA'able memory chunks
 * according to "size", "align" and "count" arguments. "ppc" is
 * pointed to a linear array of USB page caches afterwards.
 *
 * If the "align" argument is equal to "1" a non-contiguous allocation
 * can happen. Else if the "align" argument is greater than "1", the
 * allocation will always be contiguous in memory.
 *
 * Returns:
 *    0: Success
 * Else: Failure
 *------------------------------------------------------------------------*/
#if USB_HAVE_BUSDMA
uint8_t
usbd_transfer_setup_sub_malloc(struct usb_setup_params *parm,
    struct usb_page_cache **ppc, usb_size_t size, usb_size_t align,
    usb_size_t count)
{
    struct usb_page_cache *pc;
    struct usb_page *pg;
    void *buf;
    usb_size_t n_dma_pc;
    usb_size_t n_dma_pg;
    usb_size_t n_obj;
    usb_size_t x;
    usb_size_t y;
    usb_size_t r;
    usb_size_t z;

    USB_ASSERT(align > 0, ("Invalid alignment, 0x%08x\n",
        align));
    USB_ASSERT(size > 0, ("Invalid size = 0\n"));

    if (count == 0) {
        return (0);        /* nothing to allocate */
    }
    /*
     * Make sure that the size is aligned properly.
     */
    size = -((-size) & (-align)); /*lint !e501*/

    /*
     * Try multi-allocation chunks to reduce the number of DMA
     * allocations, hence DMA allocations are slow.
     */
    if (align == 1) {
        /* special case - non-cached multi page DMA memory */
        n_dma_pc = count;
        n_dma_pg = (2 + (size / USB_PAGE_SIZE));
        n_obj = 1;
    } else if (size >= USB_PAGE_SIZE) {
        n_dma_pc = count;
        n_dma_pg = 1;
        n_obj = 1;
    } else {
        /* compute number of objects per page */
        n_obj = (USB_PAGE_SIZE / size);
        /*
         * Compute number of DMA chunks, rounded up
         * to nearest one:
         */
        n_dma_pc = ((count + n_obj - 1) / n_obj);
        n_dma_pg = 1;
    }

    /*
     * DMA memory is allocated once, but mapped twice. That's why
     * there is one list for auto-free and another list for
     * non-auto-free which only holds the mapping and not the
     * allocation.
     */
    if (parm->buf == NULL) {
        /* reserve memory (auto-free) */
        parm->dma_page_ptr += n_dma_pc * n_dma_pg;
        parm->dma_page_cache_ptr += n_dma_pc;

        /* reserve memory (no-auto-free) */
        parm->dma_page_ptr += count * n_dma_pg;
        parm->xfer_page_cache_ptr += count;
        return (0);
    }
    for (x = 0; x != n_dma_pc; x++) {
        /* need to initialize the page cache */
        parm->dma_page_cache_ptr[x].tag_parent =
            &parm->curr_xfer->xroot->dma_parent_tag;
    }
    for (x = 0; x != count; x++) {
        /* need to initialize the page cache */
        parm->xfer_page_cache_ptr[x].tag_parent =
            &parm->curr_xfer->xroot->dma_parent_tag;
    }

    if (ppc != NULL) {
        *ppc = parm->xfer_page_cache_ptr;
    }
    r = count;            /* set remainder count */
    z = n_obj * size;        /* set allocation size */
    pc = parm->xfer_page_cache_ptr;
    pg = parm->dma_page_ptr;

    for (x = 0; x != n_dma_pc; x++) {

        if (r < n_obj) {
            /* compute last remainder */
            z = r * size;
            n_obj = r;
        }
        if (usb_pc_alloc_mem(parm->dma_page_cache_ptr,
            pg, z, align)) {
            return (1);    /* failure */
        }
        /* Set beginning of current buffer */
        buf = parm->dma_page_cache_ptr->buffer;
        /* Make room for one DMA page cache and one page */
        parm->dma_page_cache_ptr++;
        pg += n_dma_pg;

        for (y = 0; (y != n_obj); y++, r--, pc++, pg += n_dma_pg) {

            /* Load sub-chunk into DMA */
            if (usb_pc_dmamap_create(pc, size)) {
                return (1);    /* failure */
            }
            pc->buffer = USB_ADD_BYTES(buf, y * size); /*lint !e413*/
            pc->page_start = pg;

            mtx_lock(pc->tag_parent->mtx);
            (void)usb_pc_load_mem(pc, size, 1 /* synchronous */ );
            mtx_unlock(pc->tag_parent->mtx);
        }
    }

    parm->xfer_page_cache_ptr = pc;
    parm->dma_page_ptr = pg;
    return (0);
}
#endif

/*------------------------------------------------------------------------*
 *    usbd_transfer_setup_sub - transfer setup subroutine
 *
 * This function must be called from the "xfer_setup" callback of the
 * USB Host or Device controller driver when setting up an USB
 * transfer. This function will setup correct packet sizes, buffer
 * sizes, flags and more, that are stored in the "usb_xfer"
 * structure.
 *------------------------------------------------------------------------*/
void
usbd_transfer_setup_sub(struct usb_setup_params *parm)
{
    enum {
        REQ_SIZE = 8,
        MIN_PKT = 8,
    };
    struct usb_xfer *xfer = parm->curr_xfer;
    const struct usb_config *setup = parm->curr_setup;
    struct usb_endpoint_ss_comp_descriptor *ecomp;
    struct usb_endpoint_descriptor *edesc;
    struct usb_std_packet_size std_size;
    usb_frcount_t n_frlengths;
    usb_frcount_t n_frbuffers;
    usb_frcount_t x;
    uint16_t maxp_old;
    uint8_t type;
    uint8_t zmps;

    /*
     * Sanity check. The following parameters must be initialized before
     * calling this function.
     */
    if ((parm->hc_max_packet_size == 0) ||
        (parm->hc_max_packet_count == 0) ||
        (parm->hc_max_frame_size == 0)) {
        parm->err = USB_ERR_INVAL;
        goto done;
    }
    edesc = xfer->endpoint->edesc;
    ecomp = xfer->endpoint->ecomp;

    type = (edesc->bmAttributes & UE_XFERTYPE);

    xfer->flags = setup->flags;
    xfer->nframes = setup->frames;
    xfer->timeout = setup->timeout;
    xfer->callback = setup->callback;
    xfer->interval = setup->interval;
    xfer->endpointno = edesc->bEndpointAddress;
    xfer->max_packet_size = UGETW(edesc->wMaxPacketSize);
    xfer->max_packet_count = 1;
    /* make a shadow copy: */
    xfer->flags_int.usb_mode = parm->udev->flags.usb_mode;

    parm->bufsize = setup->bufsize;

    switch (parm->speed) {
    case USB_SPEED_HIGH:
        switch (type) {
        case UE_ISOCHRONOUS:
        case UE_INTERRUPT:
            xfer->max_packet_count +=
                (xfer->max_packet_size >> 11) & 3;

            /* check for invalid max packet count */
            if (xfer->max_packet_count > 3)
                xfer->max_packet_count = 3;
            break;
        default:
            break;
        }
        xfer->max_packet_size &= 0x7FF;
        break;
    case USB_SPEED_SUPER:
        xfer->max_packet_count += (xfer->max_packet_size >> 11) & 3;

        if (ecomp != NULL)
            xfer->max_packet_count += ecomp->bMaxBurst;

        if ((xfer->max_packet_count == 0) ||
            (xfer->max_packet_count > 16))
            xfer->max_packet_count = 16;

        switch (type) {
        case UE_CONTROL:
            xfer->max_packet_count = 1;
            break;
        case UE_ISOCHRONOUS:
            if (ecomp != NULL) {
                uint8_t mult;

                mult = UE_GET_SS_ISO_MULT(
                    ecomp->bmAttributes) + 1;
                if (mult > 3)
                    mult = 3;

                xfer->max_packet_count *= mult;
            }
            break;
        default:
            break;
        }
        xfer->max_packet_size &= 0x7FF;
        break;
    default:
        break;
    }
    /* range check "max_packet_count" */

    if (xfer->max_packet_count > parm->hc_max_packet_count) {
        xfer->max_packet_count = parm->hc_max_packet_count;
    }

    /* store max packet size value before filtering */

    maxp_old = xfer->max_packet_size;

    /* filter "wMaxPacketSize" according to HC capabilities */

    if ((xfer->max_packet_size > parm->hc_max_packet_size) ||
        (xfer->max_packet_size == 0)) {
        xfer->max_packet_size = parm->hc_max_packet_size;
    }
    /* filter "wMaxPacketSize" according to standard sizes */

    usbd_get_std_packet_size(&std_size, type, parm->speed);

    if (std_size.range.min || std_size.range.max) {

        if (xfer->max_packet_size < std_size.range.min) {
            xfer->max_packet_size = std_size.range.min;
        }
        if (xfer->max_packet_size > std_size.range.max) {
            xfer->max_packet_size = std_size.range.max;
        }
    } else {

        if (xfer->max_packet_size >= std_size.fixed[3]) {
            xfer->max_packet_size = std_size.fixed[3];
        } else if (xfer->max_packet_size >= std_size.fixed[2]) {
            xfer->max_packet_size = std_size.fixed[2];
        } else if (xfer->max_packet_size >= std_size.fixed[1]) {
            xfer->max_packet_size = std_size.fixed[1];
        } else {
            /* only one possibility left */
            xfer->max_packet_size = std_size.fixed[0];
        }
    }

    /*
     * Check if the max packet size was outside its allowed range
     * and clamped to a valid value:
     */
    if (maxp_old != xfer->max_packet_size)
        xfer->flags_int.maxp_was_clamped = 1;

    /* compute "max_frame_size" */

    usbd_update_max_frame_size(xfer);

    /* check interrupt interval and transfer pre-delay */

    if (type == UE_ISOCHRONOUS) {

        uint16_t frame_limit;

        xfer->interval = 0;    /* not used, must be zero */
        xfer->flags_int.isochronous_xfr = 1;    /* set flag */

        if (xfer->timeout == 0) {
            /*
             * set a default timeout in
             * case something goes wrong!
             */
            xfer->timeout = 1000 / 4;
        }
        switch (parm->speed) {
        case USB_SPEED_LOW:
        case USB_SPEED_FULL:
            frame_limit = USB_MAX_FS_ISOC_FRAMES_PER_XFER;
            xfer->fps_shift = 0;
            break;
        default:
            frame_limit = USB_MAX_HS_ISOC_FRAMES_PER_XFER;
            xfer->fps_shift = edesc->bInterval;
            if (xfer->fps_shift > 0)
                xfer->fps_shift--;
            if (xfer->fps_shift > 3)
                xfer->fps_shift = 3;
            if (xfer->flags.pre_scale_frames != 0)
                xfer->nframes <<= (3 - xfer->fps_shift);
            break;
        }

        if (xfer->nframes > frame_limit) {
            /*
             * this is not going to work
             * cross hardware
             */
            parm->err = USB_ERR_INVAL;
            goto done;
        }
        if (xfer->nframes == 0) {
            /*
             * this is not a valid value
             */
            parm->err = USB_ERR_ZERO_NFRAMES;
            goto done;
        }
    } else {

        /*
         * If a value is specified use that else check the
         * endpoint descriptor!
         */
        if (type == UE_INTERRUPT) {

            uint32_t temp;

            if (xfer->interval == 0) {

                xfer->interval = edesc->bInterval;

                switch (parm->speed) {
                case USB_SPEED_LOW:
                case USB_SPEED_FULL:
                    break;
                default:
                    /* 125us -> 1ms */
                    if (xfer->interval < 4)
                        xfer->interval = 1;
                    else if (xfer->interval > 16)
                        xfer->interval = (1 << (16 - 4));
                    else
                        xfer->interval =
                            (1 << (xfer->interval - 4));
                    break;
                }
            }

            if (xfer->interval == 0) {
                /*
                 * One millisecond is the smallest
                 * interval we support:
                 */
                xfer->interval = 1;
            }

            xfer->fps_shift = 0;
            temp = 1;

            while ((temp != 0) && (temp < xfer->interval)) {
                xfer->fps_shift++;
                temp *= 2;
            }

            switch (parm->speed) {
            case USB_SPEED_LOW:
            case USB_SPEED_FULL:
                break;
            default:
                xfer->fps_shift += 3;
                break;
            }
        }
    }

    /*
     * NOTE: we do not allow "max_packet_size" or "max_frame_size"
     * to be equal to zero when setting up USB transfers, hence
     * this leads to alot of extra code in the USB kernel.
     */

    if ((xfer->max_frame_size == 0) ||
        (xfer->max_packet_size == 0)) {

        zmps = 1;

        if ((parm->bufsize <= MIN_PKT) &&
            (type != UE_CONTROL) &&
            (type != UE_BULK)) {

            /* workaround */
            xfer->max_packet_size = MIN_PKT;
            xfer->max_packet_count = 1;
            parm->bufsize = 0;    /* automatic setup length */
            usbd_update_max_frame_size(xfer);

        } else {
            parm->err = USB_ERR_ZERO_MAXP;
            goto done;
        }

    } else {
        zmps = 0;
    }

    /*
     * check if we should setup a default
     * length:
     */

    if (parm->bufsize == 0) {

        parm->bufsize = xfer->max_frame_size;

        if (type == UE_ISOCHRONOUS) {
            parm->bufsize *= xfer->nframes;
        }
    }
    /*
     * check if we are about to setup a proxy
     * type of buffer:
     */

    if (xfer->flags.proxy_buffer) {

        /* round bufsize up */

        parm->bufsize += (xfer->max_frame_size - 1);

        if (parm->bufsize < xfer->max_frame_size) {
            /* length wrapped around */
            parm->err = USB_ERR_INVAL;
            goto done;
        }
        /* subtract remainder */

        parm->bufsize -= (parm->bufsize % xfer->max_frame_size);

        /* add length of USB device request structure, if any */

        if (type == UE_CONTROL) {
            parm->bufsize += REQ_SIZE;    /* SETUP message */
        }
    }
    xfer->max_data_length = parm->bufsize;

    /* Setup "n_frlengths" and "n_frbuffers" */

    if (type == UE_ISOCHRONOUS) {
        n_frlengths = xfer->nframes;
        n_frbuffers = 1;
    } else {

        if (type == UE_CONTROL) {
            xfer->flags_int.control_xfr = 1;
            if (xfer->nframes == 0) {
                if (parm->bufsize <= REQ_SIZE) {
                    /*
                     * there will never be any data
                     * stage
                     */
                    xfer->nframes = 1;
                } else {
                    xfer->nframes = 2;
                }
            }
        } else {
            if (xfer->nframes == 0) {
                xfer->nframes = 1;
            }
        }

        n_frlengths = xfer->nframes;
        n_frbuffers = xfer->nframes;
    }

    /*
     * check if we have room for the
     * USB device request structure:
     */

    if (type == UE_CONTROL) {

        if (xfer->max_data_length < REQ_SIZE) {
            /* length wrapped around or too small bufsize */
            parm->err = USB_ERR_INVAL;
            goto done;
        }
        xfer->max_data_length -= REQ_SIZE;
    }
    /*
     * Setup "frlengths" and shadow "frlengths" for keeping the
     * initial frame lengths when a USB transfer is complete. This
     * information is useful when computing isochronous offsets.
     */
    xfer->frlengths = parm->xfer_length_ptr;
    parm->xfer_length_ptr += 2 * n_frlengths;

    /* setup "frbuffers" */
    xfer->frbuffers = parm->xfer_page_cache_ptr;
    parm->xfer_page_cache_ptr += n_frbuffers;

    /* initialize max frame count */
    xfer->max_frame_count = xfer->nframes;

    /*
     * check if we need to setup
     * a local buffer:
     */

    if (!xfer->flags.ext_buffer) {
#if USB_HAVE_BUSDMA
        struct usb_page_search page_info;
        struct usb_page_cache *pc;

        if (usbd_transfer_setup_sub_malloc(parm,
            &pc, parm->bufsize, 1, 1)) {
            parm->err = USB_ERR_NOMEM;
        } else if (parm->buf != NULL) {

            usbd_get_page(pc, 0, &page_info);

            xfer->local_buffer = page_info.buffer;

            usbd_xfer_set_frame_offset(xfer, 0, 0);

            if ((type == UE_CONTROL) && (n_frbuffers > 1)) {
                usbd_xfer_set_frame_offset(xfer, REQ_SIZE, 1);
            }
        }
#else
        /* align data */
        parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1));

        if (parm->buf != NULL) {
            xfer->local_buffer =
                USB_ADD_BYTES(parm->buf, parm->size[0]);

            usbd_xfer_set_frame_offset(xfer, 0, 0);

            if ((type == UE_CONTROL) && (n_frbuffers > 1)) {
                usbd_xfer_set_frame_offset(xfer, REQ_SIZE, 1);
            }
        }
        parm->size[0] += parm->bufsize;

        /* align data again */
        parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1));
#endif
    }
    /*
     * Compute maximum buffer size
     */

    if (parm->bufsize_max < parm->bufsize) {
        parm->bufsize_max = parm->bufsize;
    }
#if USB_HAVE_BUSDMA
    if (xfer->flags_int.bdma_enable) {
        /*
         * Setup "dma_page_ptr".
         *
         * Proof for formula below:
         *
         * Assume there are three USB frames having length "a", "b" and
         * "c". These USB frames will at maximum need "z"
         * "usb_page" structures. "z" is given by:
         *
         * z = ((a / USB_PAGE_SIZE) + 2) + ((b / USB_PAGE_SIZE) + 2) +
         * ((c / USB_PAGE_SIZE) + 2);
         *
         * Constraining "a", "b" and "c" like this:
         *
         * (a + b + c) <= parm->bufsize
         *
         * We know that:
         *
         * z <= ((parm->bufsize / USB_PAGE_SIZE) + (3*2));
         *
         * Here is the general formula:
         */
        xfer->dma_page_ptr = parm->dma_page_ptr;
        parm->dma_page_ptr += (2 * n_frbuffers);
        parm->dma_page_ptr += (parm->bufsize / USB_PAGE_SIZE);
    }
#endif
    if (zmps) {
        /* correct maximum data length */
        xfer->max_data_length = 0;
    }
    /* subtract USB frame remainder from "hc_max_frame_size" */

    xfer->max_hc_frame_size =
        (parm->hc_max_frame_size -
        (parm->hc_max_frame_size % xfer->max_frame_size));

    if (xfer->max_hc_frame_size == 0) {
        parm->err = USB_ERR_INVAL;
        goto done;
    }

    /* initialize frame buffers */

    if (parm->buf) {
        for (x = 0; x != n_frbuffers; x++) {
            xfer->frbuffers[x].tag_parent =
                &xfer->xroot->dma_parent_tag;
#if USB_HAVE_BUSDMA
            if (xfer->flags_int.bdma_enable &&
                (parm->bufsize_max > 0)) {

                if (usb_pc_dmamap_create(
                    xfer->frbuffers + x,
                    parm->bufsize_max)) {
                    parm->err = USB_ERR_NOMEM;
                    goto done;
                }
            }
#endif
        }
    }
done:
    if (parm->err) {
        /*
         * Set some dummy values so that we avoid division by zero:
         */
        xfer->max_hc_frame_size = 1;
        xfer->max_frame_size = 1;
        xfer->max_packet_size = 1;
        xfer->max_data_length = 0;
        xfer->nframes = 0;
        xfer->max_frame_count = 0;
    }
}

static uint8_t
usbd_transfer_setup_has_bulk(const struct usb_config *setup_start,
    uint16_t n_setup)
{
    uint8_t type;

    while (n_setup--) {
        type = setup_start[n_setup].type;
        if (type == UE_BULK || type == UE_BULK_INTR ||
            type == UE_TYPE_ANY)
            return (1);
    }
    return (0);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_setup - setup an array of USB transfers
 *
 * NOTE: You must always call "usbd_transfer_unsetup" after calling
 * "usbd_transfer_setup" if success was returned.
 *
 * The idea is that the USB device driver should pre-allocate all its
 * transfers by one call to this function.
 *
 * Return values:
 *    0: Success
 * Else: Failure
 *------------------------------------------------------------------------*/
usb_error_t
usbd_transfer_setup(struct usb_device *udev,
    const uint8_t *ifaces, struct usb_xfer **ppxfer,
    const struct usb_config *setup_start, uint16_t n_setup,
    void *priv_sc, struct mtx *xfer_mtx) /*lint -e454 -e455 -e456 -e413 -e613*/
{
    const struct usb_config *setup_end = setup_start + n_setup;
    const struct usb_config *setup;
    struct usb_setup_params *parm;
    struct usb_endpoint *ep;
    struct usb_xfer_root *info;
    struct usb_xfer *xfer;
    void *buf = NULL;
    usb_error_t error = USB_ERR_NORMAL_COMPLETION;
    uint16_t n;
    uint16_t refcount;
    uint8_t do_unlock;

    WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
        "usbd_transfer_setup can sleep!");

    /* do some checking first */

    if (n_setup == 0) {
        DPRINTFN(5, "setup array has zero length!\n");
        return (USB_ERR_INVAL);
    }
    if (ifaces == 0) {
        DPRINTFN(5, "ifaces array is NULL!\n");
        return (USB_ERR_INVAL);
    }
    if (xfer_mtx == NULL) {
        DPRINTFN(5, "using global lock\n");
        xfer_mtx = &Giant;
    }

    /* more sanity checks */

    for (setup = setup_start, n = 0;
        setup != setup_end; setup++, n++) {
        if (setup->bufsize == (usb_frlength_t)-1) {
            error = USB_ERR_BAD_BUFSIZE;
            DPRINTF("invalid bufsize\n");
        }
        if (setup->callback == NULL) {
            error = USB_ERR_NO_CALLBACK;
            DPRINTF("no callback\n");
        }
        ppxfer[n] = NULL;
    }

    if (error)
        return (error);

    /* Protect scratch area */
    do_unlock = usbd_ctrl_lock(udev);

    refcount = 0;
    info = NULL;

    parm = &udev->scratch.xfer_setup[0].parm;
    (void)memset_s(parm, sizeof(*parm), 0, sizeof(*parm));

    parm->udev = udev;
    parm->speed = usbd_get_speed(udev);
    parm->hc_max_packet_count = 1;

    if (parm->speed >= USB_SPEED_MAX) {
        parm->err = USB_ERR_INVAL;
        goto done;
    }
    /* setup all transfers */

    while (1) {

        if (buf) {
            /*
             * Initialize the "usb_xfer_root" structure,
             * which is common for all our USB transfers.
             */
            info = USB_ADD_BYTES(buf, 0);

            info->memory_base = buf;
            info->memory_size = parm->size[0];

#if USB_HAVE_BUSDMA
            info->dma_page_cache_start = USB_ADD_BYTES(buf, parm->size[4]);
            info->dma_page_cache_end = USB_ADD_BYTES(buf, parm->size[5]);
#endif
            info->xfer_page_cache_start = USB_ADD_BYTES(buf, parm->size[5]);
            info->xfer_page_cache_end = USB_ADD_BYTES(buf, parm->size[2]);

            cv_init(&info->cv_drain, "WDRAIN");

            info->xfer_mtx = xfer_mtx;
#if USB_HAVE_BUSDMA
            usb_dma_tag_setup(&info->dma_parent_tag,  /*lint -e546*/
                parm->dma_tag_p, udev->bus->dma_parent_tag[0].tag,
                xfer_mtx, &usb_bdma_done_event, udev->bus->dma_bits, parm->dma_tag_max);
#endif

            info->bus = udev->bus;
            info->udev = udev;

            TAILQ_INIT(&info->done_q.head);
            info->done_q.command = &usbd_callback_wrapper;
#if USB_HAVE_BUSDMA
            TAILQ_INIT(&info->dma_q.head);
            info->dma_q.command = &usb_bdma_work_loop;
#endif
            info->done_m[0].hdr.pm_callback = &usb_callback_proc;
            info->done_m[0].xroot = info;
            info->done_m[1].hdr.pm_callback = &usb_callback_proc; /*lint +e546*/
            info->done_m[1].xroot = info;

            /*
             * In device side mode control endpoint
             * requests need to run from a separate
             * context, else there is a chance of
             * deadlock!
             */
            if (setup_start == usb_control_ep_cfg)
                info->done_p =
                    USB_BUS_CONTROL_XFER_PROC(udev->bus);
            else if (xfer_mtx == &Giant)
                info->done_p =
                    USB_BUS_GIANT_PROC(udev->bus);
            else if (usbd_transfer_setup_has_bulk(setup_start, n_setup))
                info->done_p =
                    USB_BUS_NON_GIANT_BULK_PROC(udev->bus);
            else
                info->done_p =
                    USB_BUS_NON_GIANT_ISOC_PROC(udev->bus);
        }
        /* reset sizes */

        parm->size[0] = 0;
        parm->buf = buf;
        parm->size[0] += sizeof(info[0]);

        for (setup = setup_start, n = 0;
            setup != setup_end; setup++, n++) {

            /* skip USB transfers without callbacks: */
            if (setup->callback == NULL) {
                continue;
            }
            /* see if there is a matching endpoint */
            ep = usbd_get_endpoint(udev,
                ifaces[setup->if_index], setup);

            /*
             * Check that the USB PIPE is valid and that
             * the endpoint mode is proper.
             *
             * Make sure we don't allocate a streams
             * transfer when such a combination is not
             * valid.
             */
            if ((ep == NULL) || (ep->methods == NULL) ||
                ((ep->ep_mode != USB_EP_MODE_STREAMS) &&
                (ep->ep_mode != USB_EP_MODE_DEFAULT)) ||
                (setup->stream_id != 0 &&
                (setup->stream_id >= USB_MAX_EP_STREAMS ||
                (ep->ep_mode != USB_EP_MODE_STREAMS)))) {
                if (setup->flags.no_pipe_ok)
                    continue;
                if ((setup->usb_mode != USB_MODE_DUAL) &&
                    (setup->usb_mode != udev->flags.usb_mode))
                    continue;
                parm->err = USB_ERR_NO_PIPE;
                goto done;
            }

            /* align data properly */
            parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1)); /*lint !e501*/

            /* store current setup pointer */
            parm->curr_setup = setup;

            if (buf) {
                /*
                 * Common initialization of the
                 * "usb_xfer" structure.
                 */
                xfer = USB_ADD_BYTES(buf, parm->size[0]);
                xfer->address = udev->address;
                xfer->priv_sc = priv_sc;
                xfer->xroot = info;

                usb_callout_init_mtx(&xfer->timeout_handle,
                    &udev->bus->bus_mtx, 0);
            } else {
                /*
                 * Setup a dummy xfer, hence we are
                 * writing to the "usb_xfer"
                 * structure pointed to by "xfer"
                 * before we have allocated any
                 * memory:
                 */
                xfer = &udev->scratch.xfer_setup[0].dummy;
                (void)memset_s(xfer, sizeof(*xfer), 0, sizeof(*xfer));
                refcount++;
            }

            /* set transfer endpoint pointer */
            xfer->endpoint = ep;

            /* set transfer stream ID */
            xfer->stream_id = setup->stream_id;

            parm->size[0] += sizeof(xfer[0]);
            parm->methods = xfer->endpoint->methods;
            parm->curr_xfer = xfer;

            /*
             * Call the Host or Device controller transfer
             * setup routine:
             */
            (udev->bus->methods->xfer_setup) (parm);

            /* check for error */
            if (parm->err)
                goto done;

            if (buf) {
                /*
                 * Increment the endpoint refcount. This
                 * basically prevents setting a new
                 * configuration and alternate setting
                 * when USB transfers are in use on
                 * the given interface. Search the USB
                 * code for "endpoint->refcount_alloc" if you
                 * want more information.
                 */
                USB_BUS_LOCK(info->bus);
                if (xfer->endpoint->refcount_alloc >= USB_EP_REF_MAX)
                    parm->err = USB_ERR_INVAL;

                xfer->endpoint->refcount_alloc++;

                if (xfer->endpoint->refcount_alloc == 0)
                    panic("usbd_transfer_setup(): Refcount wrapped to zero\n");
                USB_BUS_UNLOCK(info->bus);

                /*
                 * Whenever we set ppxfer[] then we
                 * also need to increment the
                 * "setup_refcount":
                 */
                info->setup_refcount++;

                /*
                 * Transfer is successfully setup and
                 * can be used:
                 */
                ppxfer[n] = xfer;
            }

            /* check for error */
            if (parm->err)
                goto done;
        }

        if (buf != NULL || parm->err != 0)
            goto done;

        /* if no transfers, nothing to do */
        if (refcount == 0)
            goto done;

        /* align data properly */
        parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1)); /*lint !e501*/

        /* store offset temporarily */
        parm->size[1] = parm->size[0];

        /*
         * The number of DMA tags required depends on
         * the number of endpoints. The current estimate
         * for maximum number of DMA tags per endpoint
         * is three:
         * 1) for loading memory
         * 2) for allocating memory
         * 3) for fixing memory [UHCI]
         */
        parm->dma_tag_max += 3 * MIN(n_setup, USB_EP_MAX);

        /*
         * DMA tags for QH, TD, Data and more.
         */
        parm->dma_tag_max += 8;

        parm->dma_tag_p += parm->dma_tag_max;

        parm->size[0] += ((uint8_t *)parm->dma_tag_p) -
            ((uint8_t *)0);

        /* align data properly */
        parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1)); /*lint !e501*/

        /* store offset temporarily */
        parm->size[3] = parm->size[0];

        parm->size[0] += ((uint8_t *)parm->dma_page_ptr) -
            ((uint8_t *)0);

        /* align data properly */
        parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1)); /*lint !e501*/

        /* store offset temporarily */
        parm->size[4] = parm->size[0];

        parm->size[0] += ((uint8_t *)parm->dma_page_cache_ptr) -
            ((uint8_t *)0);

        /* store end offset temporarily */
        parm->size[5] = parm->size[0];

        parm->size[0] += ((uint8_t *)parm->xfer_page_cache_ptr) -
            ((uint8_t *)0);

        /* store end offset temporarily */

        parm->size[2] = parm->size[0];

        /* align data properly */
        parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1)); /*lint !e501*/

        parm->size[6] = parm->size[0];

        parm->size[0] += ((uint8_t *)parm->xfer_length_ptr) -
            ((uint8_t *)0);

        /* align data properly */
        parm->size[0] += ((-parm->size[0]) & (USB_HOST_ALIGN - 1)); /*lint !e501*/

        /* allocate zeroed memory */
        buf = usbmalloc(parm->size[0], M_USB, M_WAITOK | M_ZERO);

        if (buf == NULL) {
            parm->err = USB_ERR_NOMEM;
            DPRINTFN(0, "cannot allocate memory block for "
                "configuration (%d bytes)\n",
                parm->size[0]);
            goto done;
        }
        parm->dma_tag_p = USB_ADD_BYTES(buf, parm->size[1]);
        parm->dma_page_ptr = USB_ADD_BYTES(buf, parm->size[3]);
        parm->dma_page_cache_ptr = USB_ADD_BYTES(buf, parm->size[4]);
        parm->xfer_page_cache_ptr = USB_ADD_BYTES(buf, parm->size[5]);
        parm->xfer_length_ptr = USB_ADD_BYTES(buf, parm->size[6]);
    }

done:
    if (buf) {
        if (info->setup_refcount == 0) {
            /*
             * "usbd_transfer_unsetup_sub" will unlock
             * the bus mutex before returning !
             */
            USB_BUS_LOCK(info->bus);

            /* something went wrong */
            usbd_transfer_unsetup_sub(info, 0);
        }
    }

    /* check if any errors happened */
    if (parm->err)
        usbd_transfer_unsetup(ppxfer, n_setup);

    error = parm->err;

    if (do_unlock)
        usbd_ctrl_unlock(udev);

    return (error);
} /*lint +e454 +e455 +e456 +e413 +e613*/

/*------------------------------------------------------------------------*
 *    usbd_transfer_unsetup_sub - factored out code
 *------------------------------------------------------------------------*/
static void
usbd_transfer_unsetup_sub(struct usb_xfer_root *info, uint8_t needs_delay) /*lint -e613 -e455*/
{
#if USB_HAVE_BUSDMA
    struct usb_page_cache *pc;
#endif

    USB_BUS_LOCK_ASSERT(info->bus, MA_OWNED);

    /* wait for any outstanding DMA operations */

    if (needs_delay) {
        usb_timeout_t temp;
        temp = usbd_get_dma_delay(info->udev);
        if (temp != 0) {
            usb_pause_mtx(&info->bus->bus_mtx,
                USB_MS_TO_TICKS(temp));
        }
    }

    /* make sure that our done messages are not queued anywhere */
    usb_proc_mwait(info->done_p, &info->done_m[0], &info->done_m[1]);

    USB_BUS_UNLOCK(info->bus);

#if USB_HAVE_BUSDMA
    /* free DMA'able memory, if any */
    pc = info->dma_page_cache_start;
    while (pc != info->dma_page_cache_end) {
        usb_pc_free_mem(pc);
        pc++;
    }

    /* free DMA maps in all "xfer->frbuffers" */
    pc = info->xfer_page_cache_start;
    while (pc != info->xfer_page_cache_end) {
        usb_pc_dmamap_destroy(pc);
        pc++;
    }

    /* free all DMA tags */
    usb_dma_tag_unsetup(&info->dma_parent_tag);
#endif

    cv_destroy(&info->cv_drain);

    /*
     * free the "memory_base" last, hence the "info" structure is
     * contained within the "memory_base"!
     */
    usbfree(info->memory_base, M_USB);
    info->memory_base = NULL;
}/*lint +e613 +e455*/

/*------------------------------------------------------------------------*
 *    usbd_transfer_unsetup - unsetup/free an array of USB transfers
 *
 * NOTE: All USB transfers in progress will get called back passing
 * the error code "USB_ERR_CANCELLED" before this function
 * returns.
 *------------------------------------------------------------------------*/
void
usbd_transfer_unsetup(struct usb_xfer **pxfer, uint16_t n_setup) /*lint -e454 -e456*/
{
    struct usb_xfer *xfer;
    struct usb_xfer_root *info;
    uint8_t needs_delay = 0;

    WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
        "usbd_transfer_unsetup can sleep!");

    while (n_setup--) {
        xfer = pxfer[n_setup];

        if (xfer == NULL)
            continue;

        info = xfer->xroot;

        USB_XFER_LOCK(xfer);
        USB_BUS_LOCK(info->bus);

        /*
         * HINT: when you start/stop a transfer, it might be a
         * good idea to directly use the "pxfer[]" structure:
         *
         * usbd_transfer_start(sc->pxfer[0]);
         * usbd_transfer_stop(sc->pxfer[0]);
         *
         * That way, if your code has many parts that will not
         * stop running under the same lock, in other words
         * "xfer_mtx", the usbd_transfer_start and
         * usbd_transfer_stop functions will simply return
         * when they detect a NULL pointer argument.
         *
         * To avoid any races we clear the "pxfer[]" pointer
         * while holding the private mutex of the driver:
         */
        pxfer[n_setup] = NULL;

        USB_BUS_UNLOCK(info->bus);
        USB_XFER_UNLOCK(xfer);

        usbd_transfer_drain(xfer);

#if USB_HAVE_BUSDMA
        if (xfer->flags_int.bdma_enable)
            needs_delay = 1;
#endif
        /*
         * NOTE: default endpoint does not have an
         * interface, even if endpoint->iface_index == 0
         */
        USB_BUS_LOCK(info->bus);
        xfer->endpoint->refcount_alloc--;
        USB_BUS_UNLOCK(info->bus);

        usb_callout_drain(&xfer->timeout_handle);

        USB_BUS_LOCK(info->bus);

        USB_ASSERT(info->setup_refcount != 0, ("Invalid setup "
            "reference count\n"));

        info->setup_refcount--;

        if (info->setup_refcount == 0) {
            usbd_transfer_unsetup_sub(info,
                needs_delay);
        } else {
            USB_BUS_UNLOCK(info->bus);
        }
    }
}/*lint +e454 +e456*/

/*------------------------------------------------------------------------*
 *    usbd_control_transfer_init - factored out code
 *
 * In USB Device Mode we have to wait for the SETUP packet which
 * containst the "struct usb_device_request" structure, before we can
 * transfer any data. In USB Host Mode we already have the SETUP
 * packet at the moment the USB transfer is started. This leads us to
 * having to setup the USB transfer at two different places in
 * time. This function just contains factored out control transfer
 * initialisation code, so that we don't duplicate the code.
 *------------------------------------------------------------------------*/
static void
usbd_control_transfer_init(struct usb_xfer *xfer)
{
    struct usb_device_request req;

    /* copy out the USB request header */

    usbd_copy_out(xfer->frbuffers, 0, &req, sizeof(req));

    /* setup remainder */

    xfer->flags_int.control_rem = UGETW(req.wLength);

    /* copy direction to endpoint variable */

    xfer->endpointno &= ~(UE_DIR_IN | UE_DIR_OUT);
    xfer->endpointno |=
        (req.bmRequestType & UT_READ) ? UE_DIR_IN : UE_DIR_OUT;
}

/*------------------------------------------------------------------------*
 *    usbd_control_transfer_did_data
 *
 * This function returns non-zero if a control endpoint has
 * transferred the first DATA packet after the SETUP packet.
 * Else it returns zero.
 *------------------------------------------------------------------------*/
static uint8_t
usbd_control_transfer_did_data(struct usb_xfer *xfer)
{
    struct usb_device_request req;

    /* SETUP packet is not yet sent */
    if (xfer->flags_int.control_hdr != 0)
        return (0);

    /* copy out the USB request header */
    usbd_copy_out(xfer->frbuffers, 0, &req, sizeof(req));

    /* compare remainder to the initial value */
    return (xfer->flags_int.control_rem != UGETW(req.wLength));
}

/*------------------------------------------------------------------------*
 *  usbd_setup_ctrl_transfer
 *
 * This function handles initialisation of control transfers. Control
 * transfers are special in that regard that they can both transmit
 * and receive data.
 *
 * Return values:
 *    0: Success
 * Else: Failure
 *------------------------------------------------------------------------*/
static int
usbd_setup_ctrl_transfer(struct usb_xfer *xfer)
{
    usb_frlength_t len;

    /* Check for control endpoint stall */
    if (xfer->flags.stall_pipe && xfer->flags_int.control_act) {
        /* the control transfer is no longer active */
        xfer->flags_int.control_stall = 1;
        xfer->flags_int.control_act = 0;
    } else {
        /* don't stall control transfer by default */
        xfer->flags_int.control_stall = 0;
    }

    /* Check for invalid number of frames */
    if (xfer->nframes > 2) {
        /*
         * If you need to split a control transfer, you
         * have to do one part at a time. Only with
         * non-control transfers you can do multiple
         * parts a time.
         */
        DPRINTFN(0, "Too many frames: %u\n",
            (unsigned int)xfer->nframes);
        goto error;
    }

    /*
         * Check if there is a control
         * transfer in progress:
         */
    if (xfer->flags_int.control_act) {

        if (xfer->flags_int.control_hdr) {

            /* clear send header flag */

            xfer->flags_int.control_hdr = 0;

            /* setup control transfer */
            if (xfer->flags_int.usb_mode == USB_MODE_DEVICE) {
                usbd_control_transfer_init(xfer);
            }
        }
        /* get data length */

        len = xfer->sumlen;

    } else {

        /* the size of the SETUP structure is hardcoded ! */

        if (xfer->frlengths[0] != sizeof(struct usb_device_request)) {
            DPRINTFN(0, "Wrong framelength %u != %zu\n",
                xfer->frlengths[0], sizeof(struct
                usb_device_request));
            goto error;
        }
        /* check USB mode */
        if (xfer->flags_int.usb_mode == USB_MODE_DEVICE) {

            /* check number of frames */
            if (xfer->nframes != 1) {
                /*
                     * We need to receive the setup
                     * message first so that we know the
                     * data direction!
                     */
                DPRINTF("Misconfigured transfer\n");
                goto error;
            }
            /*
             * Set a dummy "control_rem" value.  This
             * variable will be overwritten later by a
             * call to "usbd_control_transfer_init()" !
             */
            xfer->flags_int.control_rem = 0xFFFF;
        } else {

            /* setup "endpoint" and "control_rem" */

            usbd_control_transfer_init(xfer);
        }

        /* set transfer-header flag */

        xfer->flags_int.control_hdr = 1;

        /* get data length */

        len = (xfer->sumlen - sizeof(struct usb_device_request));
    }

    /* update did data flag */

    xfer->flags_int.control_did_data =
        usbd_control_transfer_did_data(xfer);

    /* check if there is a length mismatch */

    if (len > xfer->flags_int.control_rem) {
        DPRINTFN(0, "Length (%d) greater than "
            "remaining length (%d)\n", len,
            xfer->flags_int.control_rem);
        goto error;
    }
    /* check if we are doing a short transfer */

    if (xfer->flags.force_short_xfer) {
        xfer->flags_int.control_rem = 0;
    } else {
        if ((len != xfer->max_data_length) &&
            (len != xfer->flags_int.control_rem) &&
            (xfer->nframes != 1)) {
            DPRINTFN(0, "Short control transfer without "
                "force_short_xfer set\n");
            goto error;
        }
        xfer->flags_int.control_rem -= len;
    }

    /* the status part is executed when "control_act" is 0 */

    if ((xfer->flags_int.control_rem > 0) ||
        (xfer->flags.manual_status)) {
        /* don't execute the STATUS stage yet */
        xfer->flags_int.control_act = 1;

        /* sanity check */
        if ((!xfer->flags_int.control_hdr) &&
            (xfer->nframes == 1)) {
            /*
                 * This is not a valid operation!
                 */
            DPRINTFN(0, "Invalid parameter "
                "combination\n");
            goto error;
        }
    } else {
        /* time to execute the STATUS stage */
        xfer->flags_int.control_act = 0;
    }
    return (0);            /* success */

error:
    return (1);            /* failure */
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_submit - start USB hardware for the given transfer
 *
 * This function should only be called from the USB callback.
 *------------------------------------------------------------------------*/
void
usbd_transfer_submit(struct usb_xfer *xfer)
{
    struct usb_xfer_root *info;
    struct usb_bus *bus;
    usb_frcount_t x;

    info = xfer->xroot;
    bus = info->bus;

    DPRINTF("xfer=%p, endpoint=%p, nframes=%d, dir=%s\n",
        xfer, xfer->endpoint, xfer->nframes, USB_GET_DATA_ISREAD(xfer) ?
        "read" : "write");

#ifdef LOSCFG_USB_DEBUG
    if (USB_DEBUG_VAR > 0) {
        USB_BUS_LOCK(bus);

        usb_dump_endpoint(xfer->endpoint);

        USB_BUS_UNLOCK(bus);
    }
#endif

    USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);
    USB_BUS_LOCK_ASSERT(bus, MA_NOTOWNED);

    /* Only open the USB transfer once! */
    if (!xfer->flags_int.open) {
        xfer->flags_int.open = 1;

        DPRINTF("open\n");

        USB_BUS_LOCK(bus);
        (xfer->endpoint->methods->open) (xfer);
        USB_BUS_UNLOCK(bus);
    }
    /* set "transferring" flag */
    xfer->flags_int.transferring = 1;

#if USB_HAVE_POWERD
    /* increment power reference */
    usbd_transfer_power_ref(xfer, 1);
#endif
    /*
     * Check if the transfer is waiting on a queue, most
     * frequently the "done_q":
     */
    if (xfer->wait_queue) {
        USB_BUS_LOCK(bus);
        usbd_transfer_dequeue(xfer);
        USB_BUS_UNLOCK(bus);
    }
    /* clear "did_dma_delay" flag */
    xfer->flags_int.did_dma_delay = 0;

    /* clear "did_close" flag */
    xfer->flags_int.did_close = 0;

#if USB_HAVE_BUSDMA
    /* clear "bdma_setup" flag */
    xfer->flags_int.bdma_setup = 0;
#endif
    /* by default we cannot cancel any USB transfer immediately */
    xfer->flags_int.can_cancel_immed = 0;

    /* clear lengths and frame counts by default */
    xfer->sumlen = 0;
    xfer->actlen = 0;
    xfer->aframes = 0;

    /* clear any previous errors */
    xfer->error = USB_ERR_NORMAL_COMPLETION;

    /* Check if the device is still alive */
    if (info->udev->state < USB_STATE_POWERED) {
        USB_BUS_LOCK(bus);
        /*
         * Must return cancelled error code else
         * device drivers can hang.
         */
        usbd_transfer_done(xfer, USB_ERR_CANCELLED);
        USB_BUS_UNLOCK(bus);
        return;
    }

    /* sanity check */
    if (xfer->nframes == 0) {
        if (xfer->flags.stall_pipe) {
            /*
             * Special case - want to stall without transferring
             * any data:
             */
            DPRINTF("xfer=%p nframes=0: stall "
                "or clear stall!\n", xfer);
            USB_BUS_LOCK(bus);
            xfer->flags_int.can_cancel_immed = 1;
            /* start the transfer */
            usb_command_wrapper(&xfer->endpoint->
                endpoint_q[xfer->stream_id], xfer);
            USB_BUS_UNLOCK(bus);
            return;
        }
        USB_BUS_LOCK(bus);
        usbd_transfer_done(xfer, USB_ERR_INVAL);
        USB_BUS_UNLOCK(bus);
        return;
    }
    /* compute some variables */

    for (x = 0; x != xfer->nframes; x++) {
        /* make a copy of the frlenghts[] */
        xfer->frlengths[x + xfer->max_frame_count] = xfer->frlengths[x];
        /* compute total transfer length */
        xfer->sumlen += xfer->frlengths[x];
        if (xfer->sumlen < xfer->frlengths[x]) {
            /* length wrapped around */
            USB_BUS_LOCK(bus);
            usbd_transfer_done(xfer, USB_ERR_INVAL);
            USB_BUS_UNLOCK(bus);
            return;
        }
    }

    /* clear some internal flags */

    xfer->flags_int.short_xfer_ok = 0;
    xfer->flags_int.short_frames_ok = 0;

    /* check if this is a control transfer */

    if (xfer->flags_int.control_xfr) {

        if (usbd_setup_ctrl_transfer(xfer)) {
            USB_BUS_LOCK(bus);
            usbd_transfer_done(xfer, USB_ERR_STALLED);
            USB_BUS_UNLOCK(bus);
            return;
        }
    }
    /*
     * Setup filtered version of some transfer flags,
     * in case of data read direction
     */
    if (USB_GET_DATA_ISREAD(xfer)) {

        if (xfer->flags.short_frames_ok) {
            xfer->flags_int.short_xfer_ok = 1;
            xfer->flags_int.short_frames_ok = 1;
        } else if (xfer->flags.short_xfer_ok) {
            xfer->flags_int.short_xfer_ok = 1;

            /* check for control transfer */
            if (xfer->flags_int.control_xfr) {
                /*
                 * 1) Control transfers do not support
                 * reception of multiple short USB
                 * frames in host mode and device side
                 * mode, with exception of:
                 *
                 * 2) Due to sometimes buggy device
                 * side firmware we need to do a
                 * STATUS stage in case of short
                 * control transfers in USB host mode.
                 * The STATUS stage then becomes the
                 * "alt_next" to the DATA stage.
                 */
                xfer->flags_int.short_frames_ok = 1;
            }
        }
    }
    /*
     * Check if BUS-DMA support is enabled and try to load virtual
     * buffers into DMA, if any:
     */
#if USB_HAVE_BUSDMA
    if (xfer->flags_int.bdma_enable) {
        /* insert the USB transfer last in the BUS-DMA queue */
        usb_command_wrapper(&xfer->xroot->dma_q, xfer);
        return;
    }
#endif
    /*
     * Enter the USB transfer into the Host Controller or
     * Device Controller schedule:
     */
    usbd_pipe_enter(xfer);
}

/*------------------------------------------------------------------------*
 *    usbd_pipe_enter - factored out code
 *------------------------------------------------------------------------*/
void
usbd_pipe_enter(struct usb_xfer *xfer)
{
    struct usb_endpoint *ep;

    USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);

    USB_BUS_LOCK(xfer->xroot->bus);

    ep = xfer->endpoint;

    DPRINTF("enter\n");

    /* the transfer can now be cancelled */
    xfer->flags_int.can_cancel_immed = 1;

    /* enter the transfer */
    (ep->methods->enter) (xfer);

    /* check for transfer error */
    if (xfer->error) {
        /* some error has happened */
        usbd_transfer_done(xfer, (usb_error_t)0);
        USB_BUS_UNLOCK(xfer->xroot->bus);
        return;
    }

    /* start the transfer */
    usb_command_wrapper(&ep->endpoint_q[xfer->stream_id], xfer);
    USB_BUS_UNLOCK(xfer->xroot->bus);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_start - start an USB transfer
 *
 * NOTE: Calling this function more than one time will only
 *       result in a single transfer start, until the USB transfer
 *       completes.
 *------------------------------------------------------------------------*/
void
usbd_transfer_start(struct usb_xfer *xfer)
{
    if (xfer == NULL) {
        /* transfer is gone */
        return;
    }
    USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);

    /* mark the USB transfer started */

    if (!xfer->flags_int.started) {
        /* lock the BUS lock to avoid races updating flags_int */
        USB_BUS_LOCK(xfer->xroot->bus);
        xfer->flags_int.started = 1;
        USB_BUS_UNLOCK(xfer->xroot->bus);
    }
    /* check if the USB transfer callback is already transferring */

    if (xfer->flags_int.transferring) {
        return;
    }
    USB_BUS_LOCK(xfer->xroot->bus);
    /* call the USB transfer callback */
    usbd_callback_ss_done_defer(xfer);
    USB_BUS_UNLOCK(xfer->xroot->bus);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_stop - stop an USB transfer
 *
 * NOTE: Calling this function more than one time will only
 *       result in a single transfer stop.
 * NOTE: When this function returns it is not safe to free nor
 *       reuse any DMA buffers. See "usbd_transfer_drain()".
 *------------------------------------------------------------------------*/
void
usbd_transfer_stop(struct usb_xfer *xfer)
{
    struct usb_endpoint *ep;

    if (xfer == NULL) {
        /* transfer is gone */
        return;
    }
    USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);

    /* check if the USB transfer was ever opened */

    if (!xfer->flags_int.open) {
        if (xfer->flags_int.started) {
            /* nothing to do except clearing the "started" flag */
            /* lock the BUS lock to avoid races updating flags_int */
            USB_BUS_LOCK(xfer->xroot->bus);
            xfer->flags_int.started = 0;
            USB_BUS_UNLOCK(xfer->xroot->bus);
        }
        return;
    }
    /* try to stop the current USB transfer */

    USB_BUS_LOCK(xfer->xroot->bus);
    /* override any previous error */
    xfer->error = USB_ERR_CANCELLED;

    /*
     * Clear "open" and "started" when both private and USB lock
     * is locked so that we don't get a race updating "flags_int"
     */
    xfer->flags_int.open = 0;
    xfer->flags_int.started = 0;

    /*
     * Check if we can cancel the USB transfer immediately.
     */
    if (xfer->flags_int.transferring) {
        if (xfer->flags_int.can_cancel_immed &&
            (!xfer->flags_int.did_close)) {
            DPRINTF("close\n");
            /*
             * The following will lead to an USB_ERR_CANCELLED
             * error code being passed to the USB callback.
             */
            (xfer->endpoint->methods->close) (xfer);
            /* only close once */
            xfer->flags_int.did_close = 1;
        } else {
            /* need to wait for the next done callback */
        }
    } else {
        DPRINTF("close\n");

        /* close here and now */
        (xfer->endpoint->methods->close) (xfer);

        /*
         * Any additional DMA delay is done by
         * "usbd_transfer_unsetup()".
         */

        /*
         * Special case. Check if we need to restart a blocked
         * endpoint.
         */
        ep = xfer->endpoint;

        /*
         * If the current USB transfer is completing we need
         * to start the next one:
         */
        if (ep->endpoint_q[xfer->stream_id].curr == xfer) {
            usb_command_wrapper(
                &ep->endpoint_q[xfer->stream_id], NULL);
        }
    }

    USB_BUS_UNLOCK(xfer->xroot->bus);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_pending
 *
 * This function will check if an USB transfer is pending which is a
 * little bit complicated!
 * Return values:
 * 0: Not pending
 * 1: Pending: The USB transfer will receive a callback in the future.
 *------------------------------------------------------------------------*/
uint8_t
usbd_transfer_pending(struct usb_xfer *xfer)
{
    struct usb_xfer_root *info;
    struct usb_xfer_queue *pq;

    if (xfer == NULL) {
        /* transfer is gone */
        return (0);
    }
    USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);

    if (xfer->flags_int.transferring) {
        /* trivial case */
        return (1);
    }
    USB_BUS_LOCK(xfer->xroot->bus);
    if (xfer->wait_queue) {
        /* we are waiting on a queue somewhere */
        USB_BUS_UNLOCK(xfer->xroot->bus);
        return (1);
    }
    info = xfer->xroot;
    pq = &info->done_q;

    if (pq->curr == xfer) {
        /* we are currently scheduled for callback */
        USB_BUS_UNLOCK(xfer->xroot->bus);
        return (1);
    }
    /* we are not pending */
    USB_BUS_UNLOCK(xfer->xroot->bus);
    return (0);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_drain
 *
 * This function will stop the USB transfer and wait for any
 * additional BUS-DMA and HW-DMA operations to complete. Buffers that
 * are loaded into DMA can safely be freed or reused after that this
 * function has returned.
 *------------------------------------------------------------------------*/
void
usbd_transfer_drain(struct usb_xfer *xfer)
{
    WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
        "usbd_transfer_drain can sleep!");

    if (xfer == NULL) {
        /* transfer is gone */
        return;
    }
    if (xfer->xroot->xfer_mtx != &Giant) {
        USB_XFER_LOCK_ASSERT(xfer, MA_NOTOWNED);
    }
    USB_XFER_LOCK(xfer);

    usbd_transfer_stop(xfer);

    while (usbd_transfer_pending(xfer) ||
        xfer->flags_int.doing_callback) {

        /*
         * It is allowed that the callback can drop its
         * transfer mutex. In that case checking only
         * "usbd_transfer_pending()" is not enough to tell if
         * the USB transfer is fully drained. We also need to
         * check the internal "doing_callback" flag.
         */
        xfer->flags_int.draining = 1;

        /*
         * Wait until the current outstanding USB
         * transfer is complete !
         */
        (void)cv_wait(&xfer->xroot->cv_drain, xfer->xroot->xfer_mtx);
    }
    USB_XFER_UNLOCK(xfer);
}

struct usb_page_cache *
usbd_xfer_get_frame(struct usb_xfer *xfer, usb_frcount_t frindex)
{
    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    return (&xfer->frbuffers[frindex]);
}

void *
usbd_xfer_get_frame_buffer(struct usb_xfer *xfer, usb_frcount_t frindex)
{
    struct usb_page_search page_info;

    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    usbd_get_page(&xfer->frbuffers[frindex], 0, &page_info);
    return (page_info.buffer);
}

/*------------------------------------------------------------------------*
 *    usbd_xfer_get_fps_shift
 *
 * The following function is only useful for isochronous transfers. It
 * returns how many times the frame execution rate has been shifted
 * down.
 *
 * Return value:
 * Success: 0..3
 * Failure: 0
 *------------------------------------------------------------------------*/
uint8_t
usbd_xfer_get_fps_shift(struct usb_xfer *xfer)
{
    return (xfer->fps_shift);
}

usb_frlength_t
usbd_xfer_frame_len(struct usb_xfer *xfer, usb_frcount_t frindex)
{
    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    return (xfer->frlengths[frindex]);
}

/*------------------------------------------------------------------------*
 *    usbd_xfer_set_frame_data
 *
 * This function sets the pointer of the buffer that should
 * loaded directly into DMA for the given USB frame. Passing "ptr"
 * equal to NULL while the corresponding "frlength" is greater
 * than zero gives undefined results!
 *------------------------------------------------------------------------*/
void
usbd_xfer_set_frame_data(struct usb_xfer *xfer, usb_frcount_t frindex,
    void *ptr, usb_frlength_t len)
{
    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    /* set virtual address to load and length */
    xfer->frbuffers[frindex].buffer = ptr;
    usbd_xfer_set_frame_len(xfer, frindex, len);
}

void
usbd_xfer_frame_data(struct usb_xfer *xfer, usb_frcount_t frindex,
    void **ptr, int *len)
{
    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    if (ptr != NULL)
        *ptr = xfer->frbuffers[frindex].buffer;
    if (len != NULL)
        *len = xfer->frlengths[frindex];
}

/*------------------------------------------------------------------------*
 *    usbd_xfer_old_frame_length
 *
 * This function returns the framelength of the given frame at the
 * time the transfer was submitted. This function can be used to
 * compute the starting data pointer of the next isochronous frame
 * when an isochronous transfer has completed.
 *------------------------------------------------------------------------*/
usb_frlength_t
usbd_xfer_old_frame_length(struct usb_xfer *xfer, usb_frcount_t frindex)
{
    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    return (xfer->frlengths[frindex + xfer->max_frame_count]);
}

void
usbd_xfer_status(struct usb_xfer *xfer, int *actlen, int *sumlen, int *aframes,
    int *nframes)
{
    if (actlen != NULL)
        *actlen = xfer->actlen;
    if (sumlen != NULL)
        *sumlen = xfer->sumlen;
    if (aframes != NULL)
        *aframes = xfer->aframes;
    if (nframes != NULL)
        *nframes = xfer->nframes;
}

/*------------------------------------------------------------------------*
 *    usbd_xfer_set_frame_offset
 *
 * This function sets the frame data buffer offset relative to the beginning
 * of the USB DMA buffer allocated for this USB transfer.
 *------------------------------------------------------------------------*/
void
usbd_xfer_set_frame_offset(struct usb_xfer *xfer, usb_frlength_t offset,
    usb_frcount_t frindex)
{
    KASSERT(!xfer->flags.ext_buffer, ("Cannot offset data frame "
        "when the USB buffer is external\n"));
    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    /* set virtual address to load */
    xfer->frbuffers[frindex].buffer =
        USB_ADD_BYTES(xfer->local_buffer, offset); /*lint !e413*/
}

void
usbd_xfer_set_interval(struct usb_xfer *xfer, int i)
{
    xfer->interval = i;
}

void
usbd_xfer_set_timeout(struct usb_xfer *xfer, int t)
{
    xfer->timeout = t;
}

void
usbd_xfer_set_frames(struct usb_xfer *xfer, usb_frcount_t n)
{
    xfer->nframes = n;
}

usb_frcount_t
usbd_xfer_max_frames(struct usb_xfer *xfer)
{
    return (xfer->max_frame_count);
}

usb_frlength_t
usbd_xfer_max_len(struct usb_xfer *xfer)
{
    return (xfer->max_data_length);
}

usb_frlength_t
usbd_xfer_max_framelen(struct usb_xfer *xfer)
{
    return (xfer->max_frame_size);
}

void
usbd_xfer_set_frame_len(struct usb_xfer *xfer, usb_frcount_t frindex,
    usb_frlength_t len)
{
    KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));

    xfer->frlengths[frindex] = len;
}

/*------------------------------------------------------------------------*
 *    usb_callback_proc - factored out code
 *
 * This function performs USB callbacks.
 *------------------------------------------------------------------------*/
static void
usb_callback_proc(struct usb_proc_msg *_pm) /*lint -e454 -e455*/
{
    struct usb_done_msg *pm = (void *)_pm;
    struct usb_xfer_root *info = pm->xroot;

    /* Change locking order */
    USB_BUS_UNLOCK(info->bus);

    /*
     * We exploit the fact that the mutex is the same for all
     * callbacks that will be called from this thread:
     */
    mtx_lock(info->xfer_mtx);
    USB_BUS_LOCK(info->bus);

    /* Continue where we lost track */
    usb_command_wrapper(&info->done_q,
        info->done_q.curr);

    mtx_unlock(info->xfer_mtx);
}/*lint +e454 +e455*/

/*------------------------------------------------------------------------*
 *    usbd_callback_ss_done_defer
 *
 * This function will defer the start, stop and done callback to the
 * correct thread.
 *------------------------------------------------------------------------*/
static void
usbd_callback_ss_done_defer(struct usb_xfer *xfer)
{
    struct usb_xfer_root *info = xfer->xroot;
    struct usb_xfer_queue *pq = &info->done_q;

    USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);

    if (pq->curr != xfer) {
        usbd_transfer_enqueue(pq, xfer);
    }
    if (!pq->recurse_1) {

        /*
             * We have to postpone the callback due to the fact we
             * will have a Lock Order Reversal, LOR, if we try to
             * proceed !
             */
        if (usb_proc_msignal(info->done_p,
            &info->done_m[0], &info->done_m[1])) {
            /* ignore */
        }
    } else {
        /* clear second recurse flag */
        pq->recurse_2 = 0;
    }
    return;

}

/*------------------------------------------------------------------------*
 *    usbd_callback_wrapper
 *
 * This is a wrapper for USB callbacks. This wrapper does some
 * auto-magic things like figuring out if we can call the callback
 * directly from the current context or if we need to wakeup the
 * interrupt process.
 *------------------------------------------------------------------------*/
static void
usbd_callback_wrapper(struct usb_xfer_queue *pq) /*lint -e454 -e455*/
{
    struct usb_xfer *xfer = pq->curr;
    struct usb_xfer_root *info = xfer->xroot;

    USB_BUS_LOCK_ASSERT(info->bus, MA_OWNED);
    if (!mtx_owned(info->xfer_mtx) && !SCHEDULER_STOPPED()) { /*lint !e506*/
        /*
         * Cases that end up here:
         *
         * 5) HW interrupt done callback or other source.
         */
        DPRINTFN(3, "case 5\n");

        /*
             * We have to postpone the callback due to the fact we
             * will have a Lock Order Reversal, LOR, if we try to
             * proceed !
             */
        if (usb_proc_msignal(info->done_p,
            &info->done_m[0], &info->done_m[1])) {
            /* ignore */
        }
        return;
    }
    /*
     * Cases that end up here:
     *
     * 1) We are starting a transfer
     * 2) We are prematurely calling back a transfer
     * 3) We are stopping a transfer
     * 4) We are doing an ordinary callback
     */
    DPRINTFN(3, "case 1-4\n");
    /* get next USB transfer in the queue */
    info->done_q.curr = NULL;

    /* set flag in case of drain */
    xfer->flags_int.doing_callback = 1;

    USB_BUS_UNLOCK(info->bus);
    USB_BUS_LOCK_ASSERT(info->bus, MA_NOTOWNED);

    /* set correct USB state for callback */
    if (!xfer->flags_int.transferring) {
        xfer->usb_state = USB_ST_SETUP;
        if (!xfer->flags_int.started) {
            /* we got stopped before we even got started */
            USB_BUS_LOCK(info->bus);
            goto done;
        }
    } else {

        if (usbd_callback_wrapper_sub(xfer)) {
            /* the callback has been deferred */
            USB_BUS_LOCK(info->bus);
            goto done;
        }
#if USB_HAVE_POWERD
        /* decrement power reference */
        usbd_transfer_power_ref(xfer, -1);
#endif
        xfer->flags_int.transferring = 0;

        if (xfer->error) {
            xfer->usb_state = USB_ST_ERROR;
        } else {
            /* set transferred state */
            xfer->usb_state = USB_ST_TRANSFERRED;
#if USB_HAVE_BUSDMA
            /* sync DMA memory, if any */
            if (xfer->flags_int.bdma_enable &&
                (!xfer->flags_int.bdma_no_post_sync)) {
                usb_bdma_post_sync(xfer);
            }
#endif
        }
    }

#if USB_HAVE_PF
    if (xfer->usb_state != USB_ST_SETUP) {
        USB_BUS_LOCK(info->bus);
        usbpf_xfertap(xfer, USBPF_XFERTAP_DONE);
        USB_BUS_UNLOCK(info->bus);
    }
#endif
    /* call processing routine */
    (xfer->callback) (xfer, xfer->error);

    /* pickup the USB mutex again */
    USB_BUS_LOCK(info->bus);

    /*
     * Check if we got started after that we got cancelled, but
     * before we managed to do the callback.
     */
    if ((!xfer->flags_int.open) &&
        (xfer->flags_int.started) &&
        (xfer->usb_state == USB_ST_ERROR)) {
        /* clear flag in case of drain */
        xfer->flags_int.doing_callback = 0;
        /* try to loop, but not recursivly */
        usb_command_wrapper(&info->done_q, xfer);
        return;
    }

done:
    /* clear flag in case of drain */
    xfer->flags_int.doing_callback = 0;

    /*
     * Check if we are draining.
     */
    if (xfer->flags_int.draining &&
        (!xfer->flags_int.transferring)) {
        /* "usbd_transfer_drain()" is waiting for end of transfer */
        xfer->flags_int.draining = 0;
        (void)cv_broadcast(&info->cv_drain);
    }

    /* do the next callback, if any */
    usb_command_wrapper(&info->done_q,
        info->done_q.curr);
}/*lint +e454 +e455*/

/*------------------------------------------------------------------------*
 *    usb_dma_delay_done_cb
 *
 * This function is called when the DMA delay has been exectuded, and
 * will make sure that the callback is called to complete the USB
 * transfer. This code path is ususally only used when there is an USB
 * error like USB_ERR_CANCELLED.
 *------------------------------------------------------------------------*/
void
usb_dma_delay_done_cb(struct usb_xfer *xfer)
{
    USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);

    DPRINTFN(3, "Completed %p\n", xfer);

    /* queue callback for execution, again */
    usbd_transfer_done(xfer, (usb_error_t)0);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_dequeue
 *
 *  - This function is used to remove an USB transfer from a USB
 *  transfer queue.
 *
 *  - This function can be called multiple times in a row.
 *------------------------------------------------------------------------*/
void
usbd_transfer_dequeue(struct usb_xfer *xfer)
{
    struct usb_xfer_queue *pq;
    UINTPTR uvIntSave;

    uvIntSave = LOS_IntLock();
    pq = xfer->wait_queue;
    if (pq != NULL) {
        TAILQ_REMOVE(&pq->head, xfer, wait_entry);
        xfer->wait_queue = NULL;
    }
    LOS_IntRestore(uvIntSave);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_enqueue
 *
 *  - This function is used to insert an USB transfer into a USB *
 *  transfer queue.
 *
 *  - This function can be called multiple times in a row.
 *------------------------------------------------------------------------*/
void
usbd_transfer_enqueue(struct usb_xfer_queue *pq, struct usb_xfer *xfer)
{
    UINTPTR uvIntSave;
    /*
     * Insert the USB transfer into the queue, if it is not
     * already on a USB transfer queue:
     */
    uvIntSave = LOS_IntLock();
    if (xfer->wait_queue == NULL) {
        xfer->wait_queue = pq;
        TAILQ_INSERT_TAIL(&pq->head, xfer, wait_entry);
    }
    LOS_IntRestore(uvIntSave);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_done
 *
 *  - This function is used to remove an USB transfer from the busdma,
 *  pipe or interrupt queue.
 *
 *  - This function is used to queue the USB transfer on the done
 *  queue.
 *
 *  - This function is used to stop any USB transfer timeouts.
 *------------------------------------------------------------------------*/
void
usbd_transfer_done(struct usb_xfer *xfer, usb_error_t error)
{
    struct usb_xfer_root *info = xfer->xroot;

    USB_BUS_LOCK_ASSERT(info->bus, MA_OWNED);

    DPRINTF("err=%s\n", usbd_errstr(error));

    /*
     * If we are not transferring then just return.
     * This can happen during transfer cancel.
     */
    if (!xfer->flags_int.transferring) {
        DPRINTF("not transferring\n");
        /* end of control transfer, if any */
        xfer->flags_int.control_act = 0;
        return;
    }
    /* only set transfer error, if not already set */
    if (xfer->error == USB_ERR_NORMAL_COMPLETION)
        xfer->error = error;

    /* stop any callouts */
    usb_callout_stop(&xfer->timeout_handle);

    /*
     * If we are waiting on a queue, just remove the USB transfer
     * from the queue, if any. We should have the required locks
     * locked to do the remove when this function is called.
     */
    usbd_transfer_dequeue(xfer);

#if USB_HAVE_BUSDMA
    if (mtx_owned(info->xfer_mtx)) {
        struct usb_xfer_queue *pq;

        /*
         * If the private USB lock is not locked, then we assume
         * that the BUS-DMA load stage has been passed:
         */
        pq = &info->dma_q;

        if (pq->curr == xfer) {
            /* start the next BUS-DMA load, if any */
            usb_command_wrapper(pq, NULL);
        }
    }
#endif
    /* keep some statistics */
    if (xfer->error) {
        info->bus->stats_err.uds_requests
            [xfer->endpoint->edesc->bmAttributes & UE_XFERTYPE]++;
    } else {
        info->bus->stats_ok.uds_requests
            [xfer->endpoint->edesc->bmAttributes & UE_XFERTYPE]++;
    }

    /* call the USB transfer callback */
    usbd_callback_ss_done_defer(xfer);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_start_cb
 *
 * This function is called to start the USB transfer when
 * "xfer->interval" is greater than zero, and and the endpoint type is
 * BULK or CONTROL.
 *------------------------------------------------------------------------*/
static void
usbd_transfer_start_cb(void *arg)
{
    struct usb_xfer *xfer = arg;
    struct usb_endpoint *ep = xfer->endpoint;

    USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);

    DPRINTF("start\n");

#if USB_HAVE_PF
    usbpf_xfertap(xfer, USBPF_XFERTAP_SUBMIT);
#endif

    /* the transfer can now be cancelled */
    xfer->flags_int.can_cancel_immed = 1;

    /* start USB transfer, if no error */
    if (xfer->error == 0)
        (ep->methods->start) (xfer);

    /* check for transfer error */
    if (xfer->error) {
        /* some error has happened */
        usbd_transfer_done(xfer, (usb_error_t)0);
    }
}

/*------------------------------------------------------------------------*
 *    usbd_xfer_set_stall
 *
 * This function is used to set the stall flag outside the
 * callback. This function is NULL safe.
 *------------------------------------------------------------------------*/
void
usbd_xfer_set_stall(struct usb_xfer *xfer)
{
    if (xfer == NULL) {
        /* tearing down */
        return;
    }
    USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);

    /* avoid any races by locking the USB mutex */
    USB_BUS_LOCK(xfer->xroot->bus);
    xfer->flags.stall_pipe = 1;
    USB_BUS_UNLOCK(xfer->xroot->bus);
}

int
usbd_xfer_is_stalled(struct usb_xfer *xfer)
{
    return (xfer->endpoint->is_stalled);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_clear_stall
 *
 * This function is used to clear the stall flag outside the
 * callback. This function is NULL safe.
 *------------------------------------------------------------------------*/
void
usbd_transfer_clear_stall(struct usb_xfer *xfer)
{
    if (xfer == NULL) {
        /* tearing down */
        return;
    }
    USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);

    /* avoid any races by locking the USB mutex */
    USB_BUS_LOCK(xfer->xroot->bus);

    xfer->flags.stall_pipe = 0;

    USB_BUS_UNLOCK(xfer->xroot->bus);
}

/*------------------------------------------------------------------------*
 *    usbd_pipe_start
 *
 * This function is used to add an USB transfer to the pipe transfer list.
 *------------------------------------------------------------------------*/
void
usbd_pipe_start(struct usb_xfer_queue *pq)
{
    struct usb_endpoint *ep;
    struct usb_xfer *xfer;
    uint8_t type;

    xfer = pq->curr;
    ep = xfer->endpoint;

    USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);

    /*
     * If the endpoint is already stalled we do nothing !
     */
    if (ep->is_stalled) {
        DPRINTFN(1,"is_stalled\n");
        return;
    }
    /*
     * Check if we are supposed to stall the endpoint:
     */
    if (xfer->flags.stall_pipe) {
        struct usb_device *udev;
        struct usb_xfer_root *info;

        /* clear stall command */
        xfer->flags.stall_pipe = 0;

        /* get pointer to USB device */
        info = xfer->xroot;
        udev = info->udev;

        /*
         * Only stall BULK and INTERRUPT endpoints.
         */
        type = (ep->edesc->bmAttributes & UE_XFERTYPE);
        if ((type == UE_BULK) ||
            (type == UE_INTERRUPT)) {
            uint8_t did_stall;

            did_stall = 1;

            if (udev->flags.usb_mode == USB_MODE_DEVICE) {
                (udev->bus->methods->set_stall) (
                    udev, ep, &did_stall);
            } else if (udev->ctrl_xfer[1]) {
                info = udev->ctrl_xfer[1]->xroot;
                (void)usb_proc_msignal(
                    USB_BUS_CS_PROC(info->bus),
                    &udev->cs_msg[0], &udev->cs_msg[1]);
            } else {
                /* should not happen */
                DPRINTFN(0, "No stall handler\n");
            }
            /*
             * Check if we should stall. Some USB hardware
             * handles set- and clear-stall in hardware.
             */
            if (did_stall) {
                /*
                 * The transfer will be continued when
                 * the clear-stall control endpoint
                 * message is received.
                 */
                ep->is_stalled = 1;
                DPRINTFN(1,"did_stall\n");
                return;
            }
        } else if (type == UE_ISOCHRONOUS) {

            /*
             * Make sure any FIFO overflow or other FIFO
             * error conditions go away by resetting the
             * endpoint FIFO through the clear stall
             * method.
             */
            if (udev->flags.usb_mode == USB_MODE_DEVICE) {
                (udev->bus->methods->clear_stall) (udev, ep);
            }
        }
    }
    /* Set or clear stall complete - special case */
    if (xfer->nframes == 0) {
        /* we are complete */
        xfer->aframes = 0;
        usbd_transfer_done(xfer, (usb_error_t)0);
        DPRINTFN(1,"nframes == 0\n");
        return;
    }
    /*
     * Handled cases:
     *
     * 1) Start the first transfer queued.
     *
     * 2) Re-start the current USB transfer.
     */
    /*
     * Check if there should be any
     * pre transfer start delay:
     */
    if (xfer->interval > 0) {
        type = (ep->edesc->bmAttributes & UE_XFERTYPE);
        if ((type == UE_BULK) ||
            (type == UE_CONTROL)) {
            usbd_transfer_timeout_ms(xfer,
                &usbd_transfer_start_cb, /*lint !e546*/
                xfer->interval);
            DPRINTFN(1,"usbd_transfer_timeout_ms \n");
            return;
        }
    }

    usbd_transfer_start_cb((void *)xfer);
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_timeout_ms
 *
 * This function is used to setup a timeout on the given USB
 * transfer. If the timeout has been deferred the callback given by
 * "cb" will get called after "ms" milliseconds.
 *------------------------------------------------------------------------*/
void
usbd_transfer_timeout_ms(struct usb_xfer *xfer,
    void (*cb) (void *arg), usb_timeout_t ms)
{
    USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);

    /* defer delay */
    usb_callout_reset(&xfer->timeout_handle,
        USB_MS_TO_TICKS(ms) + USB_CALLOUT_ZERO_TICKS, cb, xfer);
}

/*------------------------------------------------------------------------*
 *    usbd_callback_wrapper_sub
 *
 *  - This function will update variables in an USB transfer after
 *  that the USB transfer is complete.
 *
 *  - This function is used to start the next USB transfer on the
 *  ep transfer queue, if any.
 *
 * NOTE: In some special cases the USB transfer will not be removed from
 * the pipe queue, but remain first. To enforce USB transfer removal call
 * this function passing the error code "USB_ERR_CANCELLED".
 *
 * Return values:
 * 0: Success.
 * Else: The callback has been deferred.
 *------------------------------------------------------------------------*/
static uint8_t
usbd_callback_wrapper_sub(struct usb_xfer *xfer)
{
    struct usb_endpoint *ep;
    struct usb_bus *bus;
    usb_frcount_t x;

    bus = xfer->xroot->bus;

    if ((!xfer->flags_int.open) &&
        (!xfer->flags_int.did_close)) {
        DPRINTF("close\n");
        USB_BUS_LOCK(bus);
        (xfer->endpoint->methods->close) (xfer);
        USB_BUS_UNLOCK(bus);
        /* only close once */
        xfer->flags_int.did_close = 1;
        return (1);        /* wait for new callback */
    }
    /*
     * If we have a non-hardware induced error we
     * need to do the DMA delay!
     */
    if (xfer->error != 0 && !xfer->flags_int.did_dma_delay &&
        (xfer->error == USB_ERR_CANCELLED ||
        xfer->error == USB_ERR_TIMEOUT ||
        bus->methods->start_dma_delay != NULL)) {

        usb_timeout_t temp;

        /* only delay once */
        xfer->flags_int.did_dma_delay = 1;

        /* we can not cancel this delay */
        xfer->flags_int.can_cancel_immed = 0;

        temp = usbd_get_dma_delay(xfer->xroot->udev);

        DPRINTFN(3, "DMA delay, %u ms, "
            "on %p\n", temp, xfer);

        if (temp != 0) {
            USB_BUS_LOCK(bus);
            /*
             * Some hardware solutions have dedicated
             * events when it is safe to free DMA'ed
             * memory. For the other hardware platforms we
             * use a static delay.
             */
            if (bus->methods->start_dma_delay != NULL) {
                (bus->methods->start_dma_delay) (xfer);
            } else {
                usbd_transfer_timeout_ms(xfer,
                    (void (*)(void *))&usb_dma_delay_done_cb, /*lint !e546*/
                    temp);
            }
            USB_BUS_UNLOCK(bus);
            return (1);    /* wait for new callback */
        }
    }
    /* check actual number of frames */
    if (xfer->aframes > xfer->nframes) {
        if (xfer->error == 0) {
            panic("%s: actual number of frames, %d, is "
                "greater than initial number of frames, %d\n",
                __FUNCTION__, xfer->aframes, xfer->nframes);
        } else {
            /* just set some valid value */
            xfer->aframes = xfer->nframes;
        }
    }
    /* compute actual length */
    xfer->actlen = 0;

    for (x = 0; x != xfer->aframes; x++) {
        xfer->actlen += xfer->frlengths[x];
    }

    /*
     * Frames that were not transferred get zero actual length in
     * case the USB device driver does not check the actual number
     * of frames transferred, "xfer->aframes":
     */
    for (; x < xfer->nframes; x++) {
        usbd_xfer_set_frame_len(xfer, x, 0);
    }

    /* check actual length */
    if (xfer->actlen > xfer->sumlen) {
        if (xfer->error == 0) {
            panic("%s: actual length, %d, is greater than "
                "initial length, %d\n",
                __FUNCTION__, xfer->actlen, xfer->sumlen);
        } else {
            /* just set some valid value */
            xfer->actlen = xfer->sumlen;
        }
    }
    DPRINTFN(1, "xfer=%p endpoint=%p sts=%d alen=%d, slen=%d, afrm=%d, nfrm=%d\n",
        xfer, xfer->endpoint, xfer->error, xfer->actlen, xfer->sumlen,
        xfer->aframes, xfer->nframes);

    if (xfer->error) {
        /* end of control transfer, if any */
        xfer->flags_int.control_act = 0;

#if USB_HAVE_TT_SUPPORT
        switch (xfer->error) {
        case USB_ERR_NORMAL_COMPLETION:
        case USB_ERR_SHORT_XFER:
        case USB_ERR_STALLED:
        case USB_ERR_CANCELLED:
            /* nothing to do */
            break;
        default:
            /* try to reset the TT, if any */
            USB_BUS_LOCK(bus);
            uhub_tt_buffer_reset_async_locked(xfer->xroot->udev, xfer->endpoint);
            USB_BUS_UNLOCK(bus);
            break;
        }
#endif
        /* check if we should block the execution queue */
        if ((xfer->error != USB_ERR_CANCELLED) &&
            (xfer->flags.pipe_bof)) {
            DPRINTFN(2, "xfer=%p: Block On Failure "
                "on endpoint=%p\n", xfer, xfer->endpoint);
            goto done;
        }
    } else {
        /* check for short transfers */
        if (xfer->actlen < xfer->sumlen) {

            /* end of control transfer, if any */
            xfer->flags_int.control_act = 0;

            if (!xfer->flags_int.short_xfer_ok) {
                xfer->error = USB_ERR_SHORT_XFER;
                if (xfer->flags.pipe_bof) {
                    DPRINTFN(2, "xfer=%p: Block On Failure on "
                        "Short Transfer on endpoint %p.\n",
                        xfer, xfer->endpoint);
                    goto done;
                }
            }
        } else {
            /*
             * Check if we are in the middle of a
             * control transfer:
             */
            if (xfer->flags_int.control_act) {
                DPRINTFN(5, "xfer=%p: Control transfer "
                    "active on endpoint=%p\n", xfer, xfer->endpoint);
                goto done;
            }
        }
    }

    ep = xfer->endpoint;

    /*
     * If the current USB transfer is completing we need to start the
     * next one:
     */
    USB_BUS_LOCK(bus);
    if (ep->endpoint_q[xfer->stream_id].curr == xfer) {
        usb_command_wrapper(&ep->endpoint_q[xfer->stream_id], NULL);

        if (ep->endpoint_q[xfer->stream_id].curr != NULL ||
            TAILQ_FIRST(&ep->endpoint_q[xfer->stream_id].head) != NULL) {
            /* there is another USB transfer waiting */
        } else {
            /* this is the last USB transfer */
            /* clear isochronous sync flag */
            xfer->endpoint->is_synced = 0;
        }
    }
    USB_BUS_UNLOCK(bus);
done:
    return (0);
}

/*------------------------------------------------------------------------*
 *    usb_command_wrapper
 *
 * This function is used to execute commands non-recursivly on an USB
 * transfer.
 *------------------------------------------------------------------------*/
void
usb_command_wrapper(struct usb_xfer_queue *pq, struct usb_xfer *xfer)
{
    UINTPTR uvIntSave;

    if (xfer) {
        /*
         * If the transfer is not already processing,
         * queue it!
         */
        if (pq->curr != xfer) {
            usbd_transfer_enqueue(pq, xfer);
            if (pq->curr != NULL) {
                /* something is already processing */
                DPRINTFN(6, "busy %p\n", pq->curr);
                return;
            }
        }
    } else {
        /* Get next element in queue */
        pq->curr = NULL;
    }

    if (!pq->recurse_1) {

        do {

            uvIntSave = LOS_IntLock();
            /* set both recurse flags */
            pq->recurse_1 = 1;
            pq->recurse_2 = 1;

            if (pq->curr == NULL) {
                xfer = TAILQ_FIRST(&pq->head);
                if (xfer) {
                    TAILQ_REMOVE(&pq->head, xfer,
                        wait_entry);
                    xfer->wait_queue = NULL;
                    pq->curr = xfer;
                } else {
                    /* clear first recurse flag */
                    pq->recurse_1 = 0;
                    LOS_IntRestore(uvIntSave);
                    break;
                }
            }
            LOS_IntRestore(uvIntSave);
            DPRINTFN(6, "cb %p (enter)\n", pq->curr);
            (pq->command) (pq);
            DPRINTFN(6, "cb %p (leave)\n", pq->curr);

            uvIntSave = LOS_IntLock();
            if(pq->recurse_2){
                /* clear first recurse flag */
                pq->recurse_1 = 0;
                LOS_IntRestore(uvIntSave);
                break;
            }
            LOS_IntRestore(uvIntSave);
        } while (1); /*lint !e506*/

    } else {
        /* clear second recurse flag */
        pq->recurse_2 = 0;
    }
}

/*------------------------------------------------------------------------*
 *    usbd_ctrl_transfer_setup
 *
 * This function is used to setup the default USB control endpoint
 * transfer.
 *------------------------------------------------------------------------*/
void
usbd_ctrl_transfer_setup(struct usb_device *udev)
{
    struct usb_xfer *xfer;
    uint8_t no_resetup;
    uint8_t iface_index;

    /* check for root HUB */
    if (udev->parent_hub == NULL)
        return;
repeat:

    xfer = udev->ctrl_xfer[0];
    if (xfer) {
        USB_XFER_LOCK(xfer);
        no_resetup =
            ((xfer->address == udev->address) &&
            (udev->ctrl_ep_desc.wMaxPacketSize[0] ==
            udev->ddesc.bMaxPacketSize));
        if (udev->flags.usb_mode == USB_MODE_DEVICE) {
            if (no_resetup) {
                /*
                 * NOTE: checking "xfer->address" and
                 * starting the USB transfer must be
                 * atomic!
                 */
                usbd_transfer_start(xfer);
            }
        }
        USB_XFER_UNLOCK(xfer);
    } else {
        no_resetup = 0;
    }

    if (no_resetup) {
        /*
             * All parameters are exactly the same like before.
             * Just return.
             */
        return;
    }
    /*
     * Update wMaxPacketSize for the default control endpoint:
     */
    udev->ctrl_ep_desc.wMaxPacketSize[0] =
        udev->ddesc.bMaxPacketSize;

    /*
     * Unsetup any existing USB transfer:
     */
    usbd_transfer_unsetup(udev->ctrl_xfer, USB_CTRL_XFER_MAX);

    /*
     * Reset clear stall error counter.
     */
    udev->clear_stall_errors = 0;

    /*
     * Try to setup a new USB transfer for the
     * default control endpoint:
     */
    iface_index = 0;
    if (usbd_transfer_setup(udev, &iface_index,
        udev->ctrl_xfer, usb_control_ep_cfg, USB_CTRL_XFER_MAX, NULL,
        &udev->device_mtx)) {
        DPRINTFN(0, "could not setup default "
            "USB transfer\n");
    } else {
        goto repeat;
    }
}

/*------------------------------------------------------------------------*
 *    usbd_clear_data_toggle - factored out code
 *
 * NOTE: the intention of this function is not to reset the hardware
 * data toggle.
 *------------------------------------------------------------------------*/
void
usbd_clear_stall_locked(struct usb_device *udev, struct usb_endpoint *ep)
{
    USB_BUS_LOCK_ASSERT(udev->bus, MA_OWNED);

    /* check that we have a valid case */
    if (udev->flags.usb_mode == USB_MODE_HOST &&
        udev->parent_hub != NULL &&
        udev->bus->methods->clear_stall != NULL &&
        ep->methods != NULL) {
        (udev->bus->methods->clear_stall) (udev, ep);
    }
}

/*------------------------------------------------------------------------*
 *    usbd_clear_data_toggle - factored out code
 *
 * NOTE: the intention of this function is not to reset the hardware
 * data toggle on the USB device side.
 *------------------------------------------------------------------------*/
void
usbd_clear_data_toggle(struct usb_device *udev, struct usb_endpoint *ep)
{
    DPRINTFN(5, "udev=%p endpoint=%p\n", udev, ep);

    USB_BUS_LOCK(udev->bus);
    ep->toggle_next = 0;
    /* some hardware needs a callback to clear the data toggle */
    usbd_clear_stall_locked(udev, ep);
    USB_BUS_UNLOCK(udev->bus);
}

/*------------------------------------------------------------------------*
 *    usbd_clear_stall_callback - factored out clear stall callback
 *
 * Input parameters:
 *  xfer1: Clear Stall Control Transfer
 *  xfer2: Stalled USB Transfer
 *
 * This function is NULL safe.
 *
 * Return values:
 *   0: In progress
 *   Else: Finished
 *
 * Clear stall config example:
 *
 * static const struct usb_config my_clearstall =  {
 *    .type = UE_CONTROL,
 *    .endpoint = 0,
 *    .direction = UE_DIR_ANY,
 *    .interval = 50, //50 milliseconds
 *    .bufsize = sizeof(struct usb_device_request),
 *    .timeout = 1000, //1.000 seconds
 *    .callback = &my_clear_stall_callback, // **
 *    .usb_mode = USB_MODE_HOST,
 * };
 *
 * ** "my_clear_stall_callback" calls "usbd_clear_stall_callback"
 * passing the correct parameters.
 *------------------------------------------------------------------------*/
uint8_t
usbd_clear_stall_callback(struct usb_xfer *xfer1,
    struct usb_xfer *xfer2)
{
    struct usb_device_request req;

    if (xfer2 == NULL) {
        /* looks like we are tearing down */
        DPRINTF("NULL input parameter\n");
        return (0);
    }
    USB_XFER_LOCK_ASSERT(xfer1, MA_OWNED);
    USB_XFER_LOCK_ASSERT(xfer2, MA_OWNED);

    switch (USB_GET_STATE(xfer1)) {
    case USB_ST_SETUP:

        /*
         * pre-clear the data toggle to DATA0 ("umass.c" and
         * "ata-usb.c" depends on this)
         */

        usbd_clear_data_toggle(xfer2->xroot->udev, xfer2->endpoint);

        /* setup a clear-stall packet */

        req.bmRequestType = UT_WRITE_ENDPOINT;
        req.bRequest = UR_CLEAR_FEATURE;
        USETW(req.wValue, UF_ENDPOINT_HALT); /*lint !e572*/
        req.wIndex[0] = xfer2->endpoint->edesc->bEndpointAddress;
        req.wIndex[1] = 0;
        USETW(req.wLength, 0); /*lint !e572*/

        /*
         * "usbd_transfer_setup_sub()" will ensure that
         * we have sufficient room in the buffer for
         * the request structure!
         */

        /* copy in the transfer */

        usbd_copy_in(xfer1->frbuffers, 0, &req, sizeof(req));

        /* set length */
        xfer1->frlengths[0] = sizeof(req);
        xfer1->nframes = 1;

        usbd_transfer_submit(xfer1);
        return (0);

    case USB_ST_TRANSFERRED:
        break;

    default:            /* Error */
        if (xfer1->error == USB_ERR_CANCELLED) {
            return (0);
        }
        break;
    }
    return (1);            /* Clear Stall Finished */
}

/*------------------------------------------------------------------------*
 *    usbd_transfer_poll
 *
 * The following function gets called from the USB keyboard driver and
 * UMASS when the system has paniced.
 *
 * NOTE: It is currently not possible to resume normal operation on
 * the USB controller which has been polled, due to clearing of the
 * "up_dsleep" and "up_msleep" flags.
 *------------------------------------------------------------------------*/
void
usbd_transfer_poll(struct usb_xfer **ppxfer, uint16_t max) /*lint -e454 -e455*/
{
    struct usb_xfer *xfer;
    struct usb_xfer_root *xroot;
    struct usb_device *udev;
    struct usb_proc_msg *pm;
    uint16_t n;
    uint16_t drop_bus;
    uint16_t drop_xfer;

    for (n = 0; n != max; n++) {
        /* Extra checks to avoid panic */
        xfer = ppxfer[n];
        if (xfer == NULL)
            continue;    /* no USB transfer */
        xroot = xfer->xroot;
        if (xroot == NULL)
            continue;    /* no USB root */
        udev = xroot->udev;
        if (udev == NULL)
            continue;    /* no USB device */
        if (udev->bus == NULL)
            continue;    /* no BUS structure */
        if (udev->bus->methods == NULL)
            continue;    /* no BUS methods */
        if (udev->bus->methods->xfer_poll == NULL)
            continue;    /* no poll method */

        /* make sure that the BUS mutex is not locked */
        drop_bus = 0;
        while (mtx_owned(&xroot->udev->bus->bus_mtx) && !SCHEDULER_STOPPED()) { /*lint !e506*/
            mtx_unlock(&xroot->udev->bus->bus_mtx);
            drop_bus++;
        }

        /* make sure that the transfer mutex is not locked */
        drop_xfer = 0;
        while (mtx_owned(xroot->xfer_mtx) && !SCHEDULER_STOPPED()) { /*lint !e506*/
            mtx_unlock(xroot->xfer_mtx);
            drop_xfer++;
        }

        /* Make sure cv_signal() and cv_broadcast() is not called */
        USB_BUS_CONTROL_XFER_PROC(udev->bus)->up_msleep = 0;
        USB_BUS_EXPLORE_PROC(udev->bus)->up_msleep = 0;
        USB_BUS_GIANT_PROC(udev->bus)->up_msleep = 0;
        USB_BUS_NON_GIANT_ISOC_PROC(udev->bus)->up_msleep = 0;
        USB_BUS_NON_GIANT_BULK_PROC(udev->bus)->up_msleep = 0;

        /* poll USB hardware */
        (udev->bus->methods->xfer_poll) (udev->bus);

        USB_BUS_LOCK(xroot->bus);

        /* check for clear stall */
        if (udev->ctrl_xfer[1] != NULL) {

            /* poll clear stall start */
            pm = &udev->cs_msg[0].hdr;
            (pm->pm_callback) (pm);
            /* poll clear stall done thread */
            pm = &udev->ctrl_xfer[1]->
                xroot->done_m[0].hdr;
            (pm->pm_callback) (pm);
        }

        /* poll done thread */
        pm = &xroot->done_m[0].hdr;
        (pm->pm_callback) (pm);

        USB_BUS_UNLOCK(xroot->bus);

        /* restore transfer mutex */
        while (drop_xfer--)
            mtx_lock(xroot->xfer_mtx);

        /* restore BUS mutex */
        while (drop_bus--)
            mtx_lock(&xroot->udev->bus->bus_mtx);
    }
}/*lint +e454 +e455*/

static void
usbd_get_std_packet_size(struct usb_std_packet_size *ptr,
    uint8_t type, enum usb_dev_speed speed) /*lint -e26*/
{
    static const uint16_t intr_range_max[USB_SPEED_MAX] = {
        [USB_SPEED_LOW] = 8,
        [USB_SPEED_FULL] = 64,
        [USB_SPEED_HIGH] = 1024,
        [USB_SPEED_VARIABLE] = 1024,
        [USB_SPEED_SUPER] = 1024,
    };

    static const uint16_t isoc_range_max[USB_SPEED_MAX] = {
        [USB_SPEED_LOW] = 0,    /* invalid */
        [USB_SPEED_FULL] = 1023,
        [USB_SPEED_HIGH] = 1024,
        [USB_SPEED_VARIABLE] = 3584,
        [USB_SPEED_SUPER] = 1024,
    };

    static const uint16_t control_min[USB_SPEED_MAX] = {
        [USB_SPEED_LOW] = 8,
        [USB_SPEED_FULL] = 8,
        [USB_SPEED_HIGH] = 64,
        [USB_SPEED_VARIABLE] = 512,
        [USB_SPEED_SUPER] = 512,
    };

    static const uint16_t bulk_min[USB_SPEED_MAX] = {
        [USB_SPEED_LOW] = 8,
        [USB_SPEED_FULL] = 8,
        [USB_SPEED_HIGH] = 512,
        [USB_SPEED_VARIABLE] = 512,
        [USB_SPEED_SUPER] = 1024,
    };

    uint16_t temp;

    (void)memset_s(ptr, sizeof(*ptr), 0, sizeof(*ptr));

    switch (type) {
    case UE_INTERRUPT:
        ptr->range.max = intr_range_max[speed];
        break;
    case UE_ISOCHRONOUS:
        ptr->range.max = isoc_range_max[speed];
        break;
    default:
        if (type == UE_BULK)
            temp = bulk_min[speed];
        else /* UE_CONTROL */
            temp = control_min[speed];

        /* default is fixed */
        ptr->fixed[0] = temp;
        ptr->fixed[1] = temp;
        ptr->fixed[2] = temp;
        ptr->fixed[3] = temp;

        if (speed == USB_SPEED_FULL) {
            /* multiple sizes */
            ptr->fixed[1] = 16;
            ptr->fixed[2] = 32;
            ptr->fixed[3] = 64;
        }
        if ((speed == USB_SPEED_VARIABLE) &&
            (type == UE_BULK)) {
            /* multiple sizes */
            ptr->fixed[2] = 1024;
            ptr->fixed[3] = 1536;
        }
        break;
    }
}/*lint +e26*/

void    *
usbd_xfer_softc(struct usb_xfer *xfer)
{
    return (xfer->priv_sc);
}

void *
usbd_xfer_get_priv(struct usb_xfer *xfer)
{
    return (xfer->priv_fifo);
}

void
usbd_xfer_set_priv(struct usb_xfer *xfer, void *ptr)
{
    xfer->priv_fifo = ptr;
}

uint8_t
usbd_xfer_state(struct usb_xfer *xfer)
{
    return (xfer->usb_state);
}

void
usbd_xfer_set_flag(struct usb_xfer *xfer, int flag)
{
    switch (flag) {
        case USB_FORCE_SHORT_XFER:
            xfer->flags.force_short_xfer = 1;
            break;
        case USB_SHORT_XFER_OK:
            xfer->flags.short_xfer_ok = 1;
            break;
        case USB_MULTI_SHORT_OK:
            xfer->flags.short_frames_ok = 1;
            break;
        case USB_MANUAL_STATUS:
            xfer->flags.manual_status = 1;
            break;
    }
}

void
usbd_xfer_clr_flag(struct usb_xfer *xfer, int flag)
{
    switch (flag) {
        case USB_FORCE_SHORT_XFER:
            xfer->flags.force_short_xfer = 0;
            break;
        case USB_SHORT_XFER_OK:
            xfer->flags.short_xfer_ok = 0;
            break;
        case USB_MULTI_SHORT_OK:
            xfer->flags.short_frames_ok = 0;
            break;
        case USB_MANUAL_STATUS:
            xfer->flags.manual_status = 0;
            break;
    }
}

/*
 * The following function returns in milliseconds when the isochronous
 * transfer was completed by the hardware. The returned value wraps
 * around 65536 milliseconds.
 */
uint16_t
usbd_xfer_get_timestamp(struct usb_xfer *xfer)
{
    return (xfer->isoc_time_complete);
}

/*
 * The following function returns non-zero if the max packet size
 * field was clamped to a valid value. Else it returns zero.
 */
uint8_t
usbd_xfer_maxp_was_clamped(struct usb_xfer *xfer)
{
    return (xfer->flags_int.maxp_was_clamped);
}

#undef USB_DEBUG_VAR
